1. Field of the Invention
This invention relates generally to protecting a surface from damage by vehicle tires and more particularly to a tire with a non-marking tread.
2. Description of Related Art
Many surfaces can be severely damaged by the mars and scuffs (marking of surface) generated by vehicle tires riding over these surfaces. Such scuffs can result in expensive and extensive clean up in order to restore the surface.
In the tire industry, it is typical that one beneficial characteristic of the tire is sacrificed when provide some other beneficial characteristic. For example, in the construction industry, aerial lift tires are designed to provide shock absorption, stability, puncture resistance, long life and traction. However, the traditional tire compound ingredients and manufacturing processes used to provide such an aerial lift tire result in a tire that has the disadvantage of marking or scuffing the surface upon which it operates.
Scuff marks are often referred to as skid marks, scours, footprints, tire marks and tread marks. Conventional tires tend to leave such marks. Common construction and building maintenance practices require that construction equipment ride over floor surfaces without creating such scuff marks. For example, construction equipment at a building site regularly operate atop concrete floors, which floors will be exposed surfaces when the building process is complete. Further, to facilitate the repair, renovation, delivery of materials and goods, and the movement of people within buildings, vehicles regularly operate over the floors of these buildings. Yet, if such buildings are, for example, medical, food processing and handling, clean rooms, auditoriums, sports arenas, shopping malls, airports, and the like, contamination and markings on the floors are unacceptable for reasons such as health, safety and appearance.
Traditional industrial anti-scuff remedies presently include solid tires that are (i) harder riding and heavier than pneumatic tires, (ii) not offered in a wide range of sizes, and (iii) not suited for riding atop soft surfaces. Other anti-scuff attempts include, but are not limited to, converting a conventional new tire having a marking tread cap to a non-marking recapped tire, or wrapping tape around the tread cap of a conventional tire, and/or spending an inordinate amount of time thoroughly cleaning the operational floor surface after it has been marked up and after the construction or repairs are completed.
Yet another example of disadvantageous non-marking designs include non-marking recapped tires produced from a conventional new tire having a normal marking tread cap compound. The new tire is sent to a retreader where the tread cap of the tire is ground off using a mechanical grinding process. A new pre-cured tread cap composed of non-marking materials is then attached to the ground down tire through a variety of bonding techniques, including vulcanizing the non-marking tread cap to the tire. This process and the resulting recapped tire have several limitations, including a high expense and environmental problems with the buffing dust. Recapping is a very costly process. Recapping costs begin with the cost of the original tire purchase, and include the cost of the recapping process, the lost time during which the equipment is inoperable because the tire has been sent out to be recapped, and the administration cost of the entire process. Since the conventional tire purchase price typically equals the retreading process price, a non-marking recapped tire is usually at least twice the cost or more of an ordinary tire.
Another conventional anti-scuff system incorporates the use of a conventional tire wrapped with tape to render the tire's tread surface non-marking. Taping of the tire may be as costly as recapping, yet even less effective. One problem associated with a taped tire is that the tape wears out fairly quickly both on the clean surface (the surface to be protected from markings), but even more quickly on an outside surface. During normal operation, the tape can rapidly deteriorate through ripping, tearing and normal wear. The resultant tire with portions of tape thereon, and portions of glue where tape has fallen off, would be incredibly difficult to clean prior to the tire re-entering the clean surface from the outside surface. Or, the tape must be fully restored over the tire to prevent tire marking. Yet a further disadvantage of this approach is the difficulty in removing the tape. Frequently the glue on the tape is transmitted to the surface of the tire, and upon removal of the tape, the tire is rendered useless. Because of these inherent inefficiencies of taping, cleaning of the operating surface is often required once the construction or repairs are complete. Another limitation of taped tires is the loss of traction between the tape and the floor surface (and the tap and the tire surface) when a taped tire is washed with water or cleaning agents prior to re-entry onto the clean surface.
Exemplary patents in this field include U.S. Pat. No. 5,439,727 to Riggs et al., which discloses an anti-scuff device that mounts, or wraps, around the surface of a tire. The anti-scuff strip is wider than the tire tread so it will overlay the tire tread and a portion of each side wall of the tire with the strip being fastened to the tire along both sides. CORDURA® PLUS is disclosed as a preferable anti-scuff material. The Riggs et al. anti-scuff material envelops a conventional tire so the tire does not contact the floor surface via the tread, but by the anti-scuff material. The Riggs et al. tire suffers from loss of traction between the tire surface and the enveloping device when the tire is cleaned with water or other cleaning agents. Riggs et al. nether teaches or suggests a process of manufacturing a non-marking tread or a tire incorporating non-marking tread.
U.S. Pat. No. 5,697,465 to Kruse discloses a personal mobility vehicle incorporating outrigger type anti-scuff wheels. Anti-scuff rollers or bumpers 86 and 88 are connected to support arms 82 and 84 positioned above the anti-tip wheels 90 and 92, respectively. The anti-scuff rollers 86 and 88 are freely rotatable about an upright axis for preventing the accidental contact with the wall by any other part of the rear of the vehicle 10. Yet, such additional rollers/bumpers increase the overall width of the vehicle, thus reducing its ability to fit through existing openings. Similarly, this patent discloses no other information about an anti-scuff roller or a process of making the roller.
It would be beneficial to provide a non-marking tire that can effectively maneuver a vehicle riding atop a first floor surface that could not tolerate contamination and tire markings, wherein the tire would also permit the same vehicle to exit the first floor surface to other types of surfaces, for example, when retrieving additional materials and/or discarding waste materials, but also enables the vehicle to effectively maneuver on those other types of floor surfaces. For re-entry of the vehicle onto the first floor surface, the non-marking tires need only be washed free of dirt or other contaminants.
Thus, it can be seen that there is a need for protecting surfaces from tire damage by using a novel tire with non-marking tread. A non-marking tread is herein defined as a tread that tends not to leave scuff marks.